Liquid ring pump

ABSTRACT

A liquid ring pump including at least one drive unit is described, having a drive shaft, a working space housing with an impeller rotating in it and axially freely movable on the drive shaft, and a disk cam with passages in the region of a front face of the drive shaft for an exchange of operating fluid for venting. The passage for the exchange of operating fluid and the axial free mobility have the effect that the impeller adjusts itself during operation.

FIELD OF THE INVENTION

The present invention relates to a liquid ring pump, comprising at leastone drive unit, having a drive shaft, and at least one working spacehousing with an impeller rotating in it and located on the drive shaft,and at least one disk cam with passages for the exchange of operatingfluid and for venting, as well as suction and pressure openings.

BACKGROUND INFORMATION

Liquid ring pumps are described in European Patent Nos. 0 517 277 and 0645 521. Each liquid ring pump includes an overhanging impeller, withwhich the gap adjustment and axial fastening are performed by means of ascrew. These adjustments prove to be very laborious and complicatedduring installation and repair work and, what is more, a special tool isrequired for this.

SUMMARY OF THE INVENTION

An object of the present invention is to simplify the operation of axialgap adjustment during both installation and repairs.

The object is successfully achieved by providing an impeller which isaxially freely movable on the drive shaft and within the working spacehousing, even during operation, and by providing a disk cam having inthe region of the front face of the drive shaft a passage for theexchange of operating fluid. During operation of the pump, the axial gapbetween the disk cam and the impeller, as well as between the impellerand the rear side of the pump, sets itself of its own accord on accountof the hydraulic conditions. These hydraulic pressure conditions areestablished as soon as the exchange of operating fluid takes place viathe passages in the disk cam in the form of bore holes or annularcutouts opposite the front side of the drive shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a mini liquid ring vacuum pump.

FIGS. 2 and 3 show polygonal and feather key connection, respectively,between a drive shaft and impeller hub.

DETAILED DESCRIPTION

The present invention is explained in more detail with reference to adrawing of a mini liquid ring vacuum pump. The drawing shows in alongitudinal section of a liquid ring pump 12 with an impeller 1, whichis located on a drive shaft 3 of a drive unit (not shown), and thecylindrical hub 2 of the impeller.

Opposite the front side 4 of the drive shaft 3 there is a passage 10arranged in a disk cam 8 and a pump cover 9 for an exchange of operatingfluid. Parallel to the drive shaft 3 there are in the hub of theimpeller 1 continuous axially parallel bore holes 6. Between the diskcam 8 and the impeller 1, and between the rear side of the pump 5 andthe impeller 1, there are the axial gaps S1 and S2, respectively.

By virtue of its design, when this liquid ring pump 12 is in operationthese gaps S1 and S2 are set of their own accord on account of thehydraulic pressure conditions. The axially movable impeller 1 has theeffect that in both gaps S1 and S2, hydraulic cushions, which areadequate for an axial adjustment of the impeller, are formed. Possibleresidues of the operating fluid, for example lime, which lead toconstriction of the gap and to blocking of the impeller 1, can beremoved by edges of the blades 13 of the impeller or the passages 6.Additional edge-forming depressions in the form of blind holes or radialgrooves in the region of the hub of the impeller 1 enhance this removingeffect.

What is claimed is:
 1. A liquid ring pump comprising: at least one driveunit, having a drive shaft; at least one impeller located on the driveshaft and rotating within a housing, the at least one impeller beingaxially movable on the drive shaft within the housing during operation;and at least one disk cam having at least one passage there through forthe exchange of an operating fluid, the at least one passage beinglocated in the region of the disk cam substantially opposite the frontface of the drive shaft.
 2. The liquid ring pump according to claim 1wherein the disk cam is further formed with at least one opening forpressure and at least one opening for suction.
 3. The liquid ring pumpaccording to claim 1 wherein the impeller is formed with a hub which isconnected to the drive shaft via a connection means selected from thegroup consisting of a polygonal connection and a feather key connection.4. A liquid ring pump according to claim 1 wherein the at least onepassage for the exchange of an operating fluid is selected from thegroup consisting of an annular cutout and a bore hole.
 5. The liquidring pump according to claim 1 wherein the impeller hub has at least oneaxially parallel bore hole which communicates with the impeller housing.